Automatic safety breaker



L. A. BROWN AUTOMATIC SAFETY BREAKER May 1o, 1927. 1,627,828'

Filed Nov. 5. '1925 2 sheets-sheet `1 May 1o; 19,21'.`

2 sheets-sheet 2 S s |f. k s Ps f f. /NW w l S .w A v w f a f .d

Patented May 10, 1927.

UNITED STATES LADURA ALEXANDER BROWN, F UNION'OUN, PENNSYLVANIA.

AUTOMATIC SAFETY BREAKER.

Application filed November 6. i925.

This invention relates to satety .switchen and more partieularlyv to salietj'y7 switches for direct current. elect ricallr driven machinerye and While useful 'for many terms of such 5 machinery it particulariffv usctul in connection with mine gi,theriugv locomotives and other mine machinery.

Gathering; locomotives and other ma chinery used in mines generally receive their ie power from a single Wire supplr7 systen'i. that is direct rurrent is used and the positive line terms a trolleyr 'wire While the negative line is grounded. These machines are provided with extension cables carried on reels Ef* in order that the machi'i y may be used beyond the trollei7 wire terminals. These cables are heavily insulated but due to the hard use they receive in the mines the insulation Otten becomes broken and the cable 2f Aforms ay short circuit with the cable reel or cable guide. These short circuits cause lires which endanger the lives of the Workmen and often times cause considerable property loss.

The presentinvention provides ay novel form et safety switch which will autoiaticalb7 break the circuit to the motor ot the machine When the cable is grounded on the cable guide or reel, and which Will prevent the ii'emaking et the motor circuit until, the cable has been disconnected from the source of current'l supply.

In the drawings: n

Figure l is a diagrammatic plan ot the circuits made and controlled by the switch.

Figure 2 is a side elevation ot the switch.

Figure 3 is an end elevation thereof.

Referring' more particularly to the drawin s. the numeral Q designates the trame ot fify the machine to which the novel switch A ot' this invention is attached. The machine is provided with the usual trolleyv 3 and cable fl. The cable 4l is carried on a reel 5 and when in use passes out over a seriesv of cable guides 6.

The cable reel 5 and cable guides 6 are in sulated from the machine 'trame 2, which frame is grounded.

The machine is provided with a. motor 77 one terminal ol' which connected to the positive feed Wire S by a Wire 9 through a controller l and the other terminal. otl which is grounded as at 11 to the machine trame.

The mining machines with which this in- Serial No. 67,300,

rentiou is adapted te he used are operated ou d' eet current. the positive line ol" which is carried in a trolleyT Wire l2 and the nega.- tire line 0' which is grounded.

The Wire S is connected through the switch A. to a Wire 'l-l and the Wire lll is connected to either the trolley 3 or cable 'il by a transfer sivitelrl.

rlhe seletjv switch A comprises a box or which eneloses theworking parts. n ii'isulatingblock 17 is secured to the casiz j lo and terms a support ttor the mag;- ne-t coils le and 19. Iron coiies or plungers 2li and Qi are mounted Within the coils 1S and f1.9, respectively, and are adapted to be reciprocated when said coils are energized. The cores 2O and 2l are connectedr by an insulating; comiecting` block 22. The block' Ql is proided with a vertically disposed slot 23 havi a horizontalljiT disposed. pin 9A exfendingtherethrough. A contact arm h loiver end mounted in the slot '23 in the block 22 and is provided with a slot 26 'to receive the pin 24ttherebT forming a conncction between the arm 25 and the block E22.

The arm 25 also passes through a slot 27 in an insulator 2S and is held therein by e.. pivot pin 29. The arm 25 is conneetedhy a conductor Ll to the Wire 14 by a post lll" and carries a pair of contacts and 3l adapted to engage stationary Contact niembers 32 and 83, respectively, at its extreme points oit movement. The Contact 32 is con.- nected at to a magnet eoil 35 supported by iron plates Bti-3G one on each side. The plates 3G 36 are bolted together through the coil and are secured to insulating supports 37H88 with their other ends open.

An are chute 40 is positioned Within the space bound by the insulating` supports 87- 3S and the iron plates 36 36 and lprojects through the top Wall et the box A.. A suitable barrier or batlie t1 is positioned Within the chute .l0 to split any are formed intotwo parts so that it may be more easily extinguished.

A hood i-2 .is positioned on the top of the bei: to prevent Watery dirt or other foreign matter entering` the hex A. through the chute 40.

In operation 'when current flowing through the coil 35 a magnetic linx is genen ated in the iron path through the coil 35 and the dui: moves across the open end of the iron plates Bti-36 Which enclose the lower end of the arc chute Ll0, thereby helping to extinguish any are formed by the operation ot the contacts H32.

rlhe coil is eonnectefgl to a post ell which in turn is connected by the wire S to the controller 10.

The Contact 2213 is connected to wires l5 and d6. rht wire a5 leads to a bell or other signal device 4t?. the other pole of which is grounded at e7, while the wire ai lead: the magnet coil lli, the other endL ot wluc i.; also grounded ai The other magnet coil .lf-l is connected by a wire with the cable reel 5 und cable guides 6 and is grounded at 4f?.

rThe contact arm 25 is normally held in position against the contact 3;, by a sprin` pressed plunger rod 50.

The operation ot the switch je is lows:

Current normally ilows from the trolley 2 or cable Liaccording to the position ot the transfer switch l5 through the conductors lit and lek to the switch tongue or arm 25 which is normally in conti 1i with the contact 3Q. rlhe current flows i .an the contact 32 through the coil 35, post fi--iand wire 8 to the controller l0, then through the wire 9 to the positive post of the motor T and then to ground.

lVhen the current is flowing through the cable 4, it due to taulty insulation or otherwise, the cable should short circuit with the cable reel or guides G, a circuit will be formed 'from the short circuit through the wire 49 and coil 19 to ground a y 8, thus energizingv coil 19 and exerting a pull on the plunger Qi which will move to the right. As the plunger 2l moves to the right contact arm 25 will be moved to the lett so as to breal; contact with the Contact 32 and thereby break the motor circuit. Tffhen the arm 25 moves to the lett contacts 31 and q" o will engage and make a circuit from the conductors isi-*lili through conductors l5 and i0 to the signal device @t7 and coil 18. respectively. The signal device being` grounded at 1LT and (he coil beineY grounded at 428.

Coil 1S being-a' thus energized exerts a pull on the plungg'er Q0 in the same direction as the pull exerted by coil 1Q on plunger 2l, thereby holding the switch arm in engage ment with contact 3?) until the power circuit broken by removal of the cable from the trolley wire. The switch arm 25 will automatically move bacl into engagement with the contact QQ immediately upon the breaking.; oilv the power circuit by the removal of `the caole Vtrom the trolleyv wire l2. However. ii the short circuit not removed the arm 25 will immediately move baelt into ensraa'ement with the conta t 323 when the cable aaain engaged with the trolley wir lVhile I have shown one speciiic embodiment ot my invention it will be understood mareas that I do not wish to be limited to the details thereof since vau'ious modiiieations may be made without depaitinfV l'rom the, scope ol. my invention as defined iu the appended claims.

l claim:

l. ln combination with a machine` a ino tor for operating the macliine. a single wire supply circuit it'or the motor .including a cable leading; from a source o? current supply', a reel 'tor said cable. a cable. guide, said cable reel and cable guide hcijg; insulated from the remainder i said machine, a .safety .switch through which the positive lead to said motor passes, said switch Colnprisingi' a casing', a stationary Contact having a lead to the motor. a movable Contact arm connected by suitable leads to said cable and normally in Contact with said stationary Contact, a in o net coil and plunger adapted to be energized b v thc current flowing through said cable reel and cable guide when said cable is grounded thereon, said coil and plunger beiia adapted to move said contact arm to b' a second staticnarj.v Contact adapted to be engaged by raid movable contact arm when said arm is caused to breal; the circuit to said motor, a second magnet coil and plunger. a connection from said second stationary Contact to said second magnet coil, said last named coil being' adapted to be euereized by the curi-eut flowing through said movable Contact arm and to hold said arm in engagement with said second named stationary contact whereby said Contact arm will not again engage said rst named stationary contact until said cable is disconnected from the source of current supply. and means tending to normally force said movable Contact arm into contact with said iirst named stationary contact.

9. In combination with a machine, a motor for operating the machine, a single wire supply circuit for the motor including a cable leading,T from a source of current supply. a reel for said cable, a cable guide, said cable reel and cable guide being insulated from the remainder of said machine, a safety switch through which the positive lead to .said motor passes, said switch comprisingr a casing, a stationary eontact having a lead to the motor, a movable Contact arm connected by suitable leads to said cable and normally in contact with said stationary Contact, a magg-net coil and plunger adapted to be energized b v the current tlmvintr through said cable reel and cable guide when said cable is grounded thereon. said coil and plunger beine adapted to move said contact arm to break the circuit to said motor, a blow-out coil mounted in said casing adjacent said stationary contact and connected in said motor circuit. said coil being adapted to generate a magnetic iiux to aid in extinl; the circuit to said motor, n

lDO

guishing any are formed by the breaking of the eireuit when the Contact arm is disengaged from the stationary Contact, a second Stationary Contact adapted to be engaged by said movable Contact arm when said arm le eaueed to break the circuit to said motor, a second magnet eoil and plunger,y a eonneetion from said eef-ond stationary eontaet to said Second magnet eoil, said last named eoil being adapted to be energized by the current .flowing through Said movable Contact arm and to hold Said arm in engagement with said seeond named stationary Contact Whereby said Contact arm will not again engage :said first named stationary Contact until Said Cable is diseolmerted from the source of Current supply, and means tending; to norinally force said movable Contact arm into Contact with Said first named Stationary contat-t.

3. In Combination with a machine, u motor for operating the marl'rine, :i Single Wire Supply circuit for the motor ii'ieluding` a cable leading from a rouree ot' current Supply, a reel for said cable. a eahle guide, Said Cable reel and cable leruide beingr insulated from the remainder oli said machine, a Safety switch through Whirl] the positive lead to said motor passes, said switch comprising a easing, a stationary Contact having a lead to the motor, a movable Contact arm connected by suit-able leads to said cable and normally in eontaet with said stationary Contact, a magnet coil and plunger adapted to be energized by the Current HOW- ing through Said Cable reel and Cable guide vwhen Said fable is grounded thereon, Said eoil and plunger beingr adapted to move said rontaet arm to break the f'irruit to said motor, a. Second stationary Contact adapted to be engaged by said movable Contact arm when said arm is caused to break the eireuit to saidr motor, a second n'iagnet Coil and plunger, a connection from said second stationary Contact to said second magnet coil, said last named Coil being adapted to be energized by the currentlowing through said movable Contact arm and to hold said arm in engagement with said Seeond named stationary Contact whereby Said Contact arm will not again engage said first named Stationary contact until said cable is disconnected `from the Source ot current Supply, and a signal connected with said second named StatiomlryT Contact and adapted to be energized when said movable Contact arm engages said eeoondnamed Stationary Contact to thereby notify the operator that the motor eireuit is broken.

In testimony whereof, I have hereunto set .my hand.

LADURA. ALEXANDER BROWN. 

